Import BDNA-22590 Hand Sti Tap 1/4-20 Unc H2 3 Flutes

Product Description

The IMPORT BDNA-22590 is a hand STI (Screw Thread Insert) tap designed to cut 1/4-20 UNC threads for Helicoil-style insert installation. It features an H2 thread limit for consistent tolerance control and a plug chamfer that allows threading to begin in a pre-drilled through-hole or a hole with sufficient depth. With 3 flutes and a bright uncoated finish, this tap is manufactured from high-speed steel (HSS) for durability across a range of workpiece materials. The overall length is 2-23/32 inches, with a thread length of 1-1/8 inches. It is sold individually and suited for repair and maintenance work in HVAC, plumbing, electrical, and mechanical trade applications.

This tap is used wherever a stripped or damaged 1/4-20 UNC threaded hole requires repair via a screw thread insert. Common applications include compressor housings, sheet metal frames, equipment panels, and any ferrous or non-ferrous component that requires a reinforced threaded insert. The plug chamfer makes it practical for most standard through-hole and deeper blind-hole threading tasks. Technicians and machinists use this tap as part of a Helicoil or equivalent STI insert repair process. The Helicoil reference number for this tap is 4CPB.

Key Features

• 1/4-20 UNC thread form for STI insert installation
• H2 thread limit for controlled tolerance fit with insert systems
• 3-flute geometry for efficient chip evacuation during hand tapping
• Plug chamfer suits through-holes and most standard-depth blind holes
• High-speed steel construction provides resistance to wear across common workpiece materials
• Bright uncoated finish — no additional coating treatment

Compatibility

Compatible with Helicoil-style screw thread insert systems requiring a 1/4-20 UNC STI tap; Helicoil reference number 4CPB. Designed for hand tapping applications in standard UNC insert repair kits.

Installation Notes

This tap is intended for hand use with a tap wrench — do not use in a powered tapping machine without confirming suitability for the feed rate. Before tapping, ensure the workpiece is secured and the correct STI drill size has been used to prepare the hole. Apply cutting fluid appropriate to the workpiece material to extend tap life and reduce the risk of breakage. Follow all applicable safety practices when working with sharp cutting tools.